1. Technical Field
The present invention relates to a fabricating method for a multilayer printed circuit board.
2. Description of the Related Art
With electronic devices being geared towards higher functionalities and smaller sizes, the need is increasing for enhancing the functions of circuit components and increasing package density. There is also a need for improving the module to which the circuit components are joined, for increasing package density and functionality. The current trend is to mount the circuit components on a circuit board having a multilayer structure, so that the package density may be improved. In particular, the multilayer printed circuit board that uses connection by inner vias is commonly utilized as a means for increasing circuit density. Furthermore, the component-integrated circuit board is being developed, in which wiring patterns connect the mounting area with the LSI areas or the components by as short a distance as possible to reduce space.
With the printed circuit board continuously becoming lighter, thinner, and simpler, the width and pitch of the circuit patterns are reaching values lower than 50 μm and even 25 μm. In such conditions of minute values, however, the circuit patterns are subject to becoming detached during the processing procedures, which can lower production yield, while bending and warpage, etc., can occur in the board. There may also be other problems affecting reliability, such as problems in migration resistance and heat resistance after moisture absorption, etc.